Study of the neutron flux in a model for a Cf-252 cold neutron source

The flux of cold neutrons that is obtainable from various high energy neutr on sources is studied for a particular model of a cold neutron source when the cold moderation region of the apparatus is at 20, 70, and 298K. The max imum flux obtained with a californium-252 source was 2.7.10(-3) cold neutro n per (cm(2).second (source neutron)). This flux was obtained when the cold moderation region of the apparatus was at 20K and when the thermal moderat or is either polyethylene or trimethylbenzene and the cold moderator is pol yethylene. This flux should allow sensitive prompt and delayed neutron acti vation analysis measurements.